Fluorescent lighting tube support



M8326, 1959 D. A. GREEN 2,888,657

FLUORESCENT LIGHTING TUBE.` SUPPORT Filed April 9, 1956 l l Ill;

United States Patent Otice 2,888,657 Patnted May ze, 1959 FLUORESCENT LIGHTING TUBE SUPPORT Daniel A. Green, Pittsburgh, Pa., assignor to Mine Safety Appliances Company, Pittsburgh, Pa., a corporation of Pennsylvania Application April 9, 1956, Serial No. 577,103

1 Claim. (Cl. 339-52) This invention relates to supports for fluorescent lighting tubes, and more particularly to such supports combined with the electrical connections for the tubes.

In most cases where iluorescent lighting tubes are mounted in stationary position, such as wall and ceiling fixtures, their supports are adequate. On lthe other hand, if such lights are to be portable and perhaps roughly handled, the present supports are not satisfactory. This is especially true Where the lights are to be used in mines where there may be explosive atmospheres. The known sockets for the ends of the tubes are not safe under such conditions because there is always the possibility of vibration or mechanical shock dislodging or momentarily interrupting the electric current to the pins at the opposite ends of the tube, thus producing a high voltage arc that may cause an explosion.

It is among the objects of this inventionto provide a combination support and electrical connection for a fluorescent lighting tube, which will hold the tube securely, and which will prevent sparking at the contact pins of the tube even though the lamp is severely jarred.

In accordance with this invention, a pair of axially spaced soft rubber sockets are fitted over the opposite ends of a fluorescent lighting tube that has a pair of contact pins projecting from each'end. Means are provided for holding the sockets in tube-receiving positions, whereby the tube will be supported resiliently. The insides of the sockets are provided with recesses, which loosely receive the tube pins. The wal-l of each recess has an opening through it, through which an electric circuit wire extends. Loosely disposed in the recesses are metal pin-gripping means that are secured to the adjoining wires for supplying current to the tube. Consequently, even though the tube and its support are subjected to vibration or shock, the pin gripping means and sockets can move freely relative to each other so that the gripping means will not loosen from the pins that they are engaging.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which- Fig. 1 is a side view of a fluorescent tube mounted in its support, with one end of the support shown in section;

Fig. 2 is a plan view of one end, with the socket partly in section; and

Fig. 3 is an exploded view of one end of the device.

Referring to Fig. 1 of the drawings, the opposite metalringed ends of a fluorescent lighting tube 1 are disposed in a pair of sockets 2, each of which is encircled by a peripheral groove 3. Each socket is mounted in a U- shaped recess 4 in a metal plate 5 which extends into the socket groove. The socket therefore is securely held by the plate, but can be quickly and easily removed from 2 it and replaced by simply sliding the socket radially into and out of recess 4. The two supporting plates are held in fixed positions the correct distance apart by any suitable means, such as a spreader bar 6 integrally joined to the plates. The spreader bar and the plates together form a long bracket which supports the sockets.

Each socket is formed from soft rubber or the like, by which is meant resilient material that can be readily compressed or flexed between the fingers. The shape of the interior of each socket is such as to permit the socket to t snugly over one end of the tube. Preferably, all of the socket that receives the end of the tube body is 1ocated at one side of supporting plate 5, and the end portion of the socket that engages the glass part of the tube may be tapered to increase its ilexibility. The two contact pins 8 projecting from each end of the tube extend into a recess 9, with which the adjoining socket is provided. The recess contains metal gripping means for frictional'ly engaging the two pins. Preferably, as shown in Figs. 2 and 3, the gripping means consists of a U- shaped spring metal clip 10 that grips both pins and therefore joins them electrically, as preferred in so-called instant start circuits. The clip ts loosely in the socket recess and is secured to the inner end of an electric circuit wire 11 which passes out of the socket through an opening connecting the back of the recess with the outside of the socket.

To mount the tube in place, the sockets generally are first pulled out of the bracket as indicated in Fig. 3. Then, the clip 10 in each socket lis pulled out of the socket and clamped over the contact pins 8 at the adjacent end of the tube. Following this, the socket is moved forward along wire 11 and over the clip and the end of the tube. The socket is held in such a position at this time that the pins and clip will enter its recess 9. After the tube has been mounted in both sockets and connected to the clips in this manner, the two sockets are inserted sideways into the recessed plates 5 at the opposite ends of the bracket. The tube is now securely but resiliently held by the sockets and cannot escape from them.

Because of the fact that the sockets are made of soft material and the small light-Weight clips are loosely disposed in the socket recesses instead of being molded into hard rubber or the like, each clip and its surrounding socket can move freely relative to each other in case the fixture is subjected to vibration or mechanical shock. Because such relative movement is permitted, the clips will remain attached to the contact pins of the tube and will not loosen from them even enough for a spark to form. that being free to move relative to the surrounding socket, it will follow the movements of the tube or remain stationary with it and not become dislodged. The tube itself, being supported by resilient material, is completely isolated from any rigid members through which vibrations might be transmitted to the tube. Such mounting contributes to the life of the tube.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, Within the scope of the appended claim, the invention may be practiced otherwise than as specically illustrated and described.

I claim:

A combination support and spark free electrical con- In other words, the mass of the clip is so small nection for a lluorescent lighting tube that has a pair of contact pins projecting from each end, comprising a pair of axially spaced soft rubber sockets adapted to receive and t snugly over the opposite ends of such a tube to resiliently support it, means holding the sockets in tubereceiving positions, the inside of the sockets being provided With recesses adapted to loosely receive said tube pins, electric circuit wires, the walls of the recesses having openings therethrough receiving the Wires, and metal pin-gripping means loosely disposed in said recesses and connected only to the Wires, said pin-gripping means being smaller than said recesses and freely movable therein and adapted to be supported solely by the contact pins gripped thereby, whereby under Vibration and shock in use said pin-gripping means and sockets can move freely 15 4 relative to each other so that the pin-gripping means will remain in tight engagement with the pins.

References Cited in the le of this patent UNITED STATES PATENTS 2,219,770 Falge et al. Oct. 29, 1940 2,284,097 La .lone May 26, 1942 2,296,114 Mueller et al. Sept. l5, 1942 2,653,303 Van Werd Sept. 22, 1953 2,677,116 Ritter Apr. 27, 1954 2,805,404 Oakes Sept. 3, 1957 FOREIGN PATENTS 228,735 Great Britain Feb. 12, 1925 

